Currently there is a lot of interest in FLARM, and it has a significant penetration in some communities (gliders especially) but I don't see it going anywhere much until a critical mass is achieved, and IMHO this will never be achieved as long as it remains a box which cannot be permanently installed in a certified aircraft and when it is installed "genuinely temporarily" the result is messy.
PowerFLARM has been STCed for all major airframes. The STC costs about 300 €.
However, the active component of it -- FLARM -- operates in the unlicensed ISM band with very low transmit power. It is basically not strong enough to provide protection for fast moving motor planes.
My concern is regarding the backlash from this tragedy.
No-one is happy to see eight people, but, more particularly, three children, die, and there is likely to be a call for extra regulation. And extra regulation for Germany is likely to mean extra regulation for the whole of Europe.
That regulation could be anything from all flights being planned and controlled to compulsory Mode S and TCAS. Either of those would kill leisure aviation dead.
But the other end of the scale of possible responses would be "People, including children, die on European roads every day, probably as many as 100 per day across Europe. Shit happens. Let's recognise that we take risks and move on."
That seems to me to be a more rational and pragmatic response.
What can we do to swing things that way?
The German ATC organization (DFS) has published the radar tracks. Before that there was speculation about the 1500ft Frankfurt TMA ceiling being responsible as every VFR plane flies at about 1500ft in a very busy area. The radar tracks show that the collision happened at 3000ft so it was outside the Frankfurt 1500ft ceiling.
The pilots were both described as experienced, one of them an active Lufthansa pilot. It looks like a very unfortunate accident without anybody to blame.
So far it doesn't look like this accident mandates regulatory changes.
It is indeed extremely unusual (by UK numbers, anyway) to get a mid-air at 3000ft.
The vast majority of UK mid-airs (about 1-2 a year) happened below 1500ft.
One recent exception was the RAF 2xGrob one which was higher but I wouldn't say the two trajectories were exactly randomised relative to each other... The RAF then fitted their Grob fleet with TCAS at, at a wild guess, £20k-25k a plane (each install includes a Sandel EHSI, this being a probably the most economic way to display the data).
I think that if GA action is needed then education on the stats (including the 3rd party risk, which is really what the public gets emotional about, being close to zero) is the best way.
The German ATC organization (DFS) has published the radar tracks.
That's commendable. Here in the UK we usually hear nothing until a year later by which time almost everybody has forgotten about it.
So far it doesn't look like this accident mandates regulatory changes.
As long as no one brings up the idea that this could have been a collision between a lightplane and an airliner. Which it could not have been in that location (there is a transponder mandatory zone around Frankfurt) but there are quite a few minor airports in Germany, where airliners spend a lot of time in airspace E during approach and departure. With no chance to be warned about non-squawking traffic around them, neither by ATC nor TCAS. And when travelling at 250kt with the very limited visibility of any jet cockpit (older Citations apart) the princible of "see and be seen" becomes a matter of sheer luck.
... compulsory Mode S and TCAS. Either of those would kill leisure aviation dead.
Personally, I am very much in favor of compulsory mode S for all airspace users. And it would not kill leisure aviation as a mode S transponder comes for less than 2500 Euros installation included. Modern microlights, even gliders, cost in excess of 50.000 Euros, so what are 2500 Euros for a potentially live saving device? As a business aviator, I fly a lot to places like Reichelsheim (where this accident occured) and on sunny afternoons and weekends it is sometimes a miracle that you don't hit anything on the way. And all those traffic warnings from ATC based on primary radar alone are pretty much useless. With production numbers large enough, even a rudimentary traffic alerting device would not cost too much, as FLARM clearly shows.
Personally, I am very much in favor of compulsory mode S for all airspace users.
I think it would be enough to require transponder equipped aircraft to always turn their transponders on. A lot of pilots know that if they fly low, they don't need a transponder and given that they don't know how to use it and have heard that it will allow ATC to identify them when they bust airspaces, they just don't use it.
Requiring a transponder on every aircraft would be tough on oldtimers and some low end microlights as transponders require a lot of power. There are still aircraft without an electric system.
I think the solution that Germany has taken isn't bad -- establish TMZs (transponder mandatory zones) around all airports with IFR procedures. Of course's there's the jet traffic to VFR places like Egelsbach or Reichelsheim.
I can't for a moment believe that mandatory Mode S (with appropriate exemptions for machines without an electrical system, etc) would kill GA dead.
This debate has been done to death in every aviation forum on earth over the past years. Here in the UK, the way I see it, the CAA lost a lot of credibility by mandating Mode S, while banning Mode C for most new installs, while not providing Mode S equipment at most radar units that serve GA, and not providing US-style traffic info on the 1090MHz data uplink, so the whole project looked like it was almost completely pointless. The "civil liberties crowd" fly with their TXP off anyway even if they have it. And Mode C is enough for TCAS purposes; Mode S doesn't appear to deliver anything to GA and doesn't appear to deliver anything to anybody else. I once visited NATS who showed a very impressive demo of managing Heathrow holding stacks with Mode S but sub-turboprop GA doesn't do that anyway.
So a lot of people think Mode S is a complete waste, and one can see why...
In the UK, Class G, VFR, you don't need Mode S, but it is de facto (practically) necessary for flying abroad.
But none of the above is going to help with GA-GA midairs.
Mandatory TCAS, currently some €10-15k, would help, but would kill much of GA.
A TMZ around Egelsbach would be an interesting concept, since it is "officially" VFR-only so the conditions must be VMC so the pilots must see everything 
So a lot of people think Mode S is a complete waste, and one can see why...
Of course it is, and us poor Germans were the first to have to replace all existing Mode A/C transponders. However, requiring every transponder equipped aircraft to always operate the transponder would work EASA wide. Later, one can think about which aircraft needs which transponder.
Funny enough, I've seen situations where ATC asked aircraft to turn off their transponders because their systems were not capable of handling the load.
Mandatory TCAS, currently some €10-15k, would kill much of GA however.
I think you're referring to TAS, not TCAS. With your Avidyne for 15k€, you won't get resolution advisories or coordination. Instead of going down the TAS route, I would much rather see mandatory ADS-B. This completely removes the need for expensive and inaccurate bearing equipment. EASA should require all manufacturers of Mode-S transponders to enable ADS-B free of charge. After all, ADS-B has always been part of the Mode S certification.
What is the ADS-B cost, by the time you display the traffic on something?
I can't for a moment believe that mandatory Mode S (with appropriate exemptions for machines without an electrical system, etc) would kill GA dead.
I just looked up a few datasheets of typical GA mode S transponders. Current drain of a Funkwerk TRT800 is 300mA at 12V. In a modern glider cockpit (all powered by a battery and sometimes solar cells) this is going to be the item that consumes the least power of all...
I think the solution that Germany has taken isn't bad -- establish TMZs (transponder mandatory zones) around all airports with IFR procedures.
There is no TMZ around every airport/airfield in Germany with IFR procedures! I would say the majority of those fields does not have a TMZ!
